Study of Selections fob Size, Shape, and Color of Hens' Eggs 267 



result from the less tension exerted by the oviduct wall on the second 

 egg when it closely follows an earlier one. After the bird has rested for 

 a day er two, the oviduct wall regains its tension and the next egg is longer. 

 The egg color, for the birds that were studied in this regard, seemed 

 to be gradually intensified in eggs laid on successive days (fig. 24). About 

 50 per cent of the cases showed an intensification of color, 25 per cent 

 showed no change, and 25 per cent showed a decrease of color. 



Variations in types of eggs produced in different calendar months 



Since it is known that the commercial eggs received in the markets 

 vary somewhat from month to month as to their average size and color, 

 and possibly as to their shape, it was thought well to ascertain what 

 information could be obtained on this point from the data at hand. These 

 variations for size, shape, and color, respectively, are illustrated in figures 

 40, 41, and 42. 



The results shown in figure 40 do not agree with those of Hadley (1919), 

 but tend instead to agree in general form with figures 28, 29, and 30. 



Grams 



Feb. 



March 



April 



May 



June 



Joly 



Aug.' 



Sept. 



Oct. 



Nov. 



Fig. 40. mean mont^y variation in size of eggs produced in certain calendar 

 t months for a period of six years. 



LAY IN FEBRUARY 



record of ten individuals beginning to 



No increase of egg size during the period of heavier production can be 

 observed here, as found by Hadley (1919) with White Plymouth Rocks. 



The results shown in figures 41 and 42 agree closely with the results 

 previously obtained for mixed flocks, and need no further comment 

 here. 



